Narrative:

After departing det, runway 33, I reached cruise altitude approximately 2100' MSL heading northbound. Leveled off and set power on cruise. 20 seconds later pilot door opened slightly emitting air draft inside cabin. Door was closed after third attempt. I had neglected to check pilot door for being secure before takeoff even though I had gone through the pretkof checklist which listed cabin doors to check for being latched. I was in a hurry to return to romeo airport before nighttime. This problem can be corrected by thoroughly going through the pretkof checklist west/O rushing and by thoroughly planning your flts and allowing for ample time between end of flight and night. After securing door, engine 'died out' to very little rpms and then jumped back to RPM setting at cruise. I did not do anything. 10 seconds after this, the engine did the same thing again. I reported engine problems and requested immediate landing at det. Tower cleared me for landing. I made turn to return to det staying at the same altitude and spiraled down to land west/O incident opting to land on runway 15. Before takeoff, I had checked the engine magnetos and for carburetor ice on the pretkof checklist. It was fine no RPM abnormality. After engine 'failure' incident I had thought it might have been magneto; head or cylinder problem as plane had 2 cylinders replaced awhile ago. I had flown it previously west/O incident after the replacement or repair. I did not think of applying carburetor heat for this reason and because I hd just taken off and checked for carburetor ice before takeoff. I should have about 200 RPM applied full power and carburetor heat and executed an immediate turn back to the airport instead of waiting for clearance due to the emergency. I should have immediately contacted ATC on 121.5 instead of waiting for channel clearance and set transponder to 7700.

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Original NASA ASRS Text

Title: GA SMA LOST ENGINE POWER AT TOP OF CLIMB, RECEIVED CLRNC TO RETURN LAND OPPOSITE DIRECTION.

Narrative: AFTER DEPARTING DET, RWY 33, I REACHED CRUISE ALT APPROX 2100' MSL HDG NBND. LEVELED OFF AND SET PWR ON CRUISE. 20 SECS LATER PLT DOOR OPENED SLIGHTLY EMITTING AIR DRAFT INSIDE CABIN. DOOR WAS CLOSED AFTER THIRD ATTEMPT. I HAD NEGLECTED TO CHK PLT DOOR FOR BEING SECURE BEFORE TKOF EVEN THOUGH I HAD GONE THROUGH THE PRETKOF CHKLIST WHICH LISTED CABIN DOORS TO CHK FOR BEING LATCHED. I WAS IN A HURRY TO RETURN TO ROMEO ARPT BEFORE NIGHTTIME. THIS PROBLEM CAN BE CORRECTED BY THOROUGHLY GOING THROUGH THE PRETKOF CHKLIST W/O RUSHING AND BY THOROUGHLY PLANNING YOUR FLTS AND ALLOWING FOR AMPLE TIME BTWN END OF FLT AND NIGHT. AFTER SECURING DOOR, ENG 'DIED OUT' TO VERY LITTLE RPMS AND THEN JUMPED BACK TO RPM SETTING AT CRUISE. I DID NOT DO ANYTHING. 10 SECS AFTER THIS, THE ENG DID THE SAME THING AGAIN. I RPTED ENG PROBS AND REQUESTED IMMEDIATE LNDG AT DET. TWR CLRED ME FOR LNDG. I MADE TURN TO RETURN TO DET STAYING AT THE SAME ALT AND SPIRALED DOWN TO LAND W/O INCIDENT OPTING TO LAND ON RWY 15. BEFORE TKOF, I HAD CHKED THE ENG MAGNETOS AND FOR CARB ICE ON THE PRETKOF CHKLIST. IT WAS FINE NO RPM ABNORMALITY. AFTER ENG 'FAILURE' INCIDENT I HAD THOUGHT IT MIGHT HAVE BEEN MAGNETO; HEAD OR CYLINDER PROB AS PLANE HAD 2 CYLINDERS REPLACED AWHILE AGO. I HAD FLOWN IT PREVIOUSLY W/O INCIDENT AFTER THE REPLACEMENT OR REPAIR. I DID NOT THINK OF APPLYING CARB HEAT FOR THIS REASON AND BECAUSE I HD JUST TAKEN OFF AND CHKED FOR CARB ICE BEFORE TKOF. I SHOULD HAVE ABOUT 200 RPM APPLIED FULL PWR AND CARB HEAT AND EXECUTED AN IMMEDIATE TURN BACK TO THE ARPT INSTEAD OF WAITING FOR CLRNC DUE TO THE EMER. I SHOULD HAVE IMMEDIATELY CONTACTED ATC ON 121.5 INSTEAD OF WAITING FOR CHANNEL CLRNC AND SET XPONDER TO 7700.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.